1. Field of the Invention
This invention relates to bicycles and other pedal device, and in particular, relates to a pedal device with increased travel distance due to a pedal and leverage arm.
2. Description of the Related Art
A bicycle, while including many variants, is basically a pedal-driven, human-powered vehicle with two wheels attached to a frame, one behind the other. The basic shape and configuration of a typical bicycle has changed little since the first chain-driven model was developed around 1885. Bicycles typically include a frame, a drive unit, and front and rear wheels that are mounted to front and rear ends of the frame, respectively. The drive unit is mounted to the frame and left and right cranks are rotatably mounted to the drive unit.
The great majority of today's bicycles have a frame with upright seating which looks much like the first chain-driven bike. Such upright bicycles almost always feature the diamond frame, a truss consisting of two triangles: the front triangle and the rear triangle. The front triangle consists of the head tube, top tube, down tube and seat tube. The head tube contains the headset, the set of bearings that allows the fork to turn smoothly for steering and balance. The top tube connects the head tube to the seat tube at the top, and the down tube connects the head tube to the bottom bracket. The rear triangle consists of the seat tube and paired chain stays and seat stays. The chain stays run parallel to the chain, connecting the bottom bracket to the rear dropouts. The seat stays connect the top of the seat tube (at or near the same point as the top tube) to the rear dropouts.
The drive train of current bicycles, as generally known in the art, begins with pedals which rotate the cranks, which are held in axis by the bottom bracket. Most bicycles use a chain to transmit power to the rear wheel. A relatively small number of bicycles use a shaft drive to transmit power. A very small number of bicycles (mainly single-speed bicycles intended for short-distance commuting) use a belt drive as an oil-free way of transmitting power.
Since cyclists' legs are most efficient over a narrow range of pedaling speeds (cadence), a variable gear ratio helps a cyclist to maintain an optimum pedaling speed while covering varied terrain. Different gears and ranges of gears are appropriate for different people and styles of cycling. Multi-speed bicycles allow gear selection to suit the circumstances: a cyclist could use a high gear when cycling downhill, a medium gear when cycling on a flat road, and a low gear when cycling uphill. In a lower gear every turn of the pedals leads to fewer rotations of the rear wheel. This allows the energy required to move the same distance to be distributed over more pedal turns, reducing fatigue when riding uphill, with a heavy load, or against strong winds. A higher gear allows a cyclist to make fewer pedal turns to maintain a given speed, but with more effort per turn of the pedals.
With a chain drive transmission, a chain ring attached to a crank drives the chain, which in turn rotates the rear wheel via the rear sprocket(s) (cassette or freewheel). There are four gearing options: two-speed hub gear integrated with chain ring, up to 3 chain rings, up to 11 sprockets, hub gear built in to rear wheel (3-speed to 14-speed). The most common options are either a rear hub or multiple chain rings combined with multiple sprockets (other combinations of options are possible but less common).
With a shaft drive transmission, a gear set at the bottom bracket turns the shaft, which then turns the rear wheel via a gear set connected to the wheel's hub. There is some small loss of efficiency due to the two gear sets needed. The only gearing option with a shaft drive is to use a hub gear.
In each of these prior drive mechanisms, two pedals turn a large gear which turns a smaller gear, generally with the use of a chain. Pushing a pedal from top to bottom means that the cyclist must push forward and then downward twice in one 360° turn of the pedal, which moves the bicycle forward. The main pedal sprocket is turned one time (or 360°), which limits the chain travel to the circumference of the sprocket for each single turn. These prior bicycles require forward motion of the pedal, during which the forward momentum of the bicycle is reduced. Normal bicycle sprockets have a diameter of 6½ inches, with a pedal to pedal distance of 13-16 inches. The sprocket travel per turn is 20.3 inches and pedal to pedal travel is 40.6 inches, and that is overcoming top dead center force twice to turn the pedal.
Other prior pedal devices rely on similar drive mechanisms in which movement of the pedals do not have uniform leverage it their various positions during the pedaling process.
It is therefore an object of the invention herein to provide a bicycle having a pedal and leverage arm, in which bicycle the cyclist's body weight is used to a more efficient potential, because the pivot point is at the rear of the bicycle and the pedal movement is straight down and up.
It is a further object of the invention to provide a bicycle in which the gear location is near the rear wheel and far behind the pedals.
Other objects and advantages will be more fully apparent from the following disclosure and appended claims.